The present invention relates to a method of confirming that a pattern to be printed is a high-density pattern and divisionally printing the pattern, and a dot printer which can print a series of high-quality, high-density patterns in accordance therewith.
As computers develop, printers have been widely used as one of the terminal devices in computer systems. As the application of printers increases, printer power sources have been reduced in size and weight, with subsequent decreases in costs.
When a high-density pattern such as an all dot (100% duty) pattern is to be printed by a conventional printer (e.g., a 24-pin serial impact dot printer), all the pins are driven at all printing positions in accordance with the pattern. When such high-density patterns are sequentially printed, power consumption increases, resulting in a decrease in the power source voltage. When pin drive voltages are decreased, changes in printing density tend to occur in the printed characters, thereby degrading printing quality. In order to prevent this problem, serial printing of high-density patterns is generally limited. In order to solve the problem of this limitation, power source capacity of the printer is increased, or the decrease in the power source voltage is detected and printing is temporarily stopped.
However, in the former case, the printer itself tends to be large in size, resulting in high costs In the latter case, printer operation is temporarily stopped after detecting the decrease in the power source voltage, or the printer is temporarily switched to divisional printing. As a result, high-duty dot printing is again enabled, without increasing the power source capacity. However, in this latter case, a detector for detecting the decrease in power source voltage is required, resulting in a complicated structure and leading to increased costs. In addition, since printing is temporarily stopped or divisional printing is performed after a decrease in the power source voltage, printing quality immediately before the voltage decrease is degraded.